#include <iostream>
using namespace std;
int main()
{
	int k;
	double s=0,i;
	cin>>k;
	if (k>=1 && k<=15)
	{
		for (i=1;;i++)
		{
			if (s<=k)
			{
				s = s + 1.000/i;
			}
			else break;
		}
		cout<<i-1<<endl;
	}
	else cout<<"Error!"<<endl;
	return 0;
}
